The mobile payment tech company Vivotech Inc. said Wednesday that it is working with DeviceFidelity Inc. to provide contactless payment capabilities for smartphones that can accept microSD memory cards.

Vivotech said that its mobile wallet software works with DeviceFidelity's cards, which are built with near-field communication chips, to allow banks to add payment capabilities to handsets that did not have those functions built in.

DeviceFidelity, of Richardson, Texas, also provides a case with a microSD slot for Apple Inc.'s iPhone 3G and iPhone 3GS, which lack memory card slots.

Although carriers and handset makers have been slow to provide phones to U.S. consumers that could make contactless payments linked to bank accounts, some companies have moved ahead with systems that provide similar functions through existing phone hardware.

In addition to the system sold by DeviceFidelity, other companies have distributed contactless payment "tags" — stickers with built-in payment chips that are meant to be adhered to phones. Bling Nation Ltd. has launched this technology with community banks in several cities; to complete the illusion that the sticker is part of the phone, Bling sends text messages after each transaction as a purchase confirmation and paperless receipt.

Starbucks Corp. uses a system from mFoundry Inc. that puts a bar code on a phone's screen to access a linked prepaid card. Target Corp. has a similar system which, though not designed by mFoundry, works with scanners that are also compatible with the Starbucks system.

Despite these deployments, mobile payment systems are still in their infancy, and DeviceFidelity said that its microSD card system can help issuers sidestep the business issues that have slowed the development of phones with built-in NFC payment chips.

"Our technology unlocks the 'chicken and egg' situation that has plagued the NFC ecosystem," Deepak Jain, DeviceFidelity's founder and chief executive, said in a press release.